Hand operated hydraulic thrusting device



July 9, 1968 P. E. ASHTON 3,391,536

HAND OPERATED HYDRAULIC THRUSTING DEVICE l Filed Oct. 24, 1966 68 s C)'i 70 11| Hl f4 f/Gg/ 56.5 INVENTOR United States Patent O M 3,391,536HAND OPERATED HYDRAUMC THRUSTiNG DEVlCE Phiiip E. Ashton, 749 Yale Ave.,Meriden, Conn. 06450 Filed Oct. 24, 1966, Ser. No. 589,092 9 Claims.(Cl. 60-52) The present invention relates to presses and othermechanisms having means of transmitting thrust through a ram or similarmember and which are operated by a combination of mechanical andhydraulic means. An object of the invention is to provide a device inwhich a ram or similar member may be thrustingly moved by mechanicalmeans until it encounters a given resistance to such movement andthereon the mode of operation changes to a hydraulic means with anaccompanying change in the overall mechanical advantage of the device.

A further object is to provide a small mechanical-hydraulic thrustproducing mechanism which may be operated, locked under load, orunlocked and have its ram retracted, all by movement of a single handlein a simple up and down motion.

Still another object is to provide a small thrust producing unit whichmay readily be mounted on, or removed from, a convenient support for useor repair.

An additional object of the invention is to provide a smallmechanical-hydraulic device wherein the rarn may be advanced through itswhole stroke in a single movement of an operating lever with relativelylow mechanical advantage or may be advanced in a plurality of stepsthrough the Same distance at a relatively high mechanical advantage by anumber of movements of the operating lever,

How these and other objects of the invention may be accomplished will beapparent in the light of the following disclosure and the accompanyingdrawings of which:

FIG. l is a side elevation of a small bench press which embodies theinvention;

FIG. 2 is a sectional elevation, on a somewhat larger scale, taken onthe centerline of the mechanism of FIG. l;

FIG. 3 is a fragmentary sectional elevation of FIG. 2, taken on the line3 3;

FIG. 4 is an enlarged sectional view of the upper part of the pumpmechanism shown in FIG. 2, and

FIG. 5 is a fragmentary side elevation of the guide and latch structureas seen from the line 5-5 of FIG. 3.

Throughout the drawings, like numerals indicate like parts.

Referring to the figures, there will be seen a support of generallyconventional design. It has a working area 11 on which tools or workpieces may be carried and over this a bracket 12 to hold a thrust unit13 comprising a ram guide 14 suitably threaded and retained by nuts 15.A ram 16 is slidingly supported in the guide 14 and is coupled to anoperating lever 17 as will be later explained. The thrust unit 13 is agenerally cylindrical housing 18 secured to the upper end of guide 14and Serves both as a reservoir for working iiuid and as a workingcylinder wherein hydraulic thrust on the ram is developed. The housing18 has a pendent forked bracket 19 on which the lever 17 is carried byfulcrum pin 20 passing through a slot 20a in the rearward end of lever17.

Turning specifically to FIG. 2 showing the thrust unit in a verticalcenter-line section. The ram guide 14 has a bearing bushing 21 at eachend, in which the ram 16 is actually carried, the said guide ispreferably threaded at the lower end for attachment to the support 10 atthe upper end for attachment to the housing 18 (though a flange joint isa suitable alternative); these threads carry the whole reaction load ofany thrust transmitted through the ram 16 to work or tools (not shown)carried in sup- 3,391,536 Patented Jury a, 196s port 10. The housing 18is preferably of cast iron and is bored to two diameters, 'a larger one88 and a smaller one 22, suitably finished to serve as a workingcylinder for piston 23 which carries a conventional O ring 34 as a seal;this affords a shoulder 24 at the junction of the two diameters. Thecylinder head 25 has two diameters to match those of the housing 18 andit is grooved at mid-height to carry an O ring 26 which has sealingengagement with the wall of the larger bore 88 and at the same time isin contact with the shoulder 24. A split spring retainer ring 27 seatsin groove 28 which is so spaced from the shoulder 24 as to hold O ring26 under compression against the said shoulder. This arrangement affordsa rugged and inexpensive way of holding the cylinder head in place. Thespace above the cylinder head 25 serves as a reservoir 89 for theworking fluid. A suction or check valve 29, of conventional constructionallows ingress of fluid from the reservoir, through head 25, into theworking cylinder but allows no tiow in the reverse direction. Anundercut 30 may be cast in place to facilitate finishing the bore 22 anda vent 30a may be provided to release air during operation.

A pump assembly 31 is mounted on the ram 16, concentric with it andpartly inside it; the pumps barrel 32 is finished externally for slidingsealing engagement with an O ring 33 located in a recess in the cylinderhead 25 and there held by the press-fitted retainer 35. The lower end ofbarrel 32 has a number of ports 36 and is closed by a plug 37 which maybe brazed in place, the said plug is drilled for the piston rod 38 andhas a counter-bore for the O ring 39 which is held in place by apress-fitted retainer 40. The ram 16 is machined out from the top tothree diameters, all co-axial with the ram, the first one 41 affords anannular Space 42 around the barrel 32, the second one 43 is a closesupporting fit for the said barrel below the lports 36 while the thirdand lower diameter 44 is sized for threading as at 45 to receive matingthreads on the lower end of plug 37 and, beyond the threads, it servesas a guide for the cross-head 46 of piston rod 38, which parts may besecured together by any convenient means, screw thread for instance.Referring to FIG. 4, there is within the pump barrel 32 a piston 47which is not secured to the piston rod 38 although movable thereby, aswill be later explained. The piston 47 has a central passage 48appreciably larger than the rod 38 which passes therethrough, and isgrooved for an O ring 49 having a sliding sealing fit with the interiorof barrel 32, said piston 47 is made cup-shaped at the top to receiveand hold an O ring 50 which has no contact with the wall of said barrel.A 'suitable bushing 51 is carried, by screw threaded engagement, on thepiston rod 38 slightly below its upper end. Below bushing 51 a cruciformwasher 52 is press-fitted on the rod 38 against a shoulder 53; as shownin FIG. 4, the piston 47 is loosely located between the said bushing andthe cruciform washer; if the piston rod 38 is moved downwards, thebushing 51 engages O ring 50, sealing the passage 48 and the piston willthereafter move downward with the piston rod, but when the motion isreversed the cruciform washer 52 will engage the lower edge of piston 47to move it upward, while the bushing 51 will be disengaged from the Oring 5t) and so open the passage 48.

The pump barrel 32 has an external screw thread 54 at its upper end andsecured thereby is a valve unit 55 which comprises body 56, ball valve57, spring 58, plug 59 and gasket 6C, the body 56 has a cavity 61internally threaded to match the thread 54, the end face of the Saidcavity is sm-ooth for sealing engagement with the end of the barrel 32and has a central and preferably square hole 62 which is sized to affordsliding support to the upper unthreaded end of piston rod 38 whileallowing the passage of iiuid. A drilling 63, of two concentricdiameters affords a shoulder 64, serving as a valve seat for valve 57,and its larger portion is threaded to take the hollow plug 59 whichserves as a carrier for spring 58; a further drilling 65 connectsdrilling 63 with the reservoir 89 and affords fluid access to the valve57. The central hole 62 traverses drilling 63 to form a recess or pocket66. If the piston rod 38 is moved upward from the position shown` inFIG. 4, its tip will strike the valve 57 and move it from its seat 64;the pocket 66 makes space for this. A split spring ring 67 is located inthe barrel 32 immediately below the body 56 to prevent piston 47contacting bushing 51 while valve 57 is being unseated. It should benoted that the above described organization of piston 47 and associatedparts constitutes a valve which is positively opened and closed by therelative movement of O ring 501 and bushing 51. Such a valve may alsoopen under suction but the use of check valve 29 to admit fluid tocylinder 22 is preferred, as if there is too much friction between Oring 49 and the barrel 32, suction may fail to overcome it.

Returning to FIG. 2, a guide sleeve 68 surrounds and is slidable onram-guide 14. In turn, it is surrounded by the mid-portion of lever 17which here forms an encircling yoke 69. As shown in FIG. 3, a wrist-pin70 passes from side to side through said yoke and sleeve 68 and alsothrough ram-guide 14, ram 16 and cross-head 46. Wrist pin 70 may besecured by conventional means or force fit into the yoke. Slots 71 and72, of similar width, are cut through said ram-guide and ramrespectively to accommodate said wrist-pin and allow it to move axiallyof them. Sleeve 68 serves to support wrist-pin 70 against movement indirections other than axially of said ram guide and said ram. Sleeve 68has a boss 73 and, secured thereto by screws 74, is a carrier plate 75.A latch pin 76 has a head 77 which is slidingly supported in a drilling78 that is a little smaller in diameter than the width of the slots 71and 72, the pins shank is similarly supported in a hole through plate75; a compression spring 79 is carried on said shank between head 77 andplate 75 to urge them apart, their relative movement being limited bythe shank being spun over as at 80. A groove 81 having divergentbevelled sides is cut in ram 16 slightly above the slots 72 which, attheir upper ends, are also bevelled. A tongue 82, which may protrudeinto the said groove, is formed on the head 77, and is bevelled to matchthe walls of groove 81, the said groove is considerably wider than thethickness of said tongue. The croSshead 46 has a boss 83 encircled by ashort stilf spring 84 which may be compressed between the said crossheadand the bottom of plug 37.

A cover 85 having a breather hole (not shown) serves as a lid over thefluid in the housing 18, and may conveniently be retained by its Skirt86, having a friction lit on O ring 87.

Operation It will be seen that the mechanism described comprises fourmajor sections; (a) the body section including housing 18 with itscylinder 22 and ram guide 14; (b) the thrusting section which includespiston 23 and ram 16; (c) the pump section comprising pump 31 and (d)the actuating section which includes lever 17, and sleeve 68 and iscoupled t pump 31 by wrist pin '70 passing through crosss-head 46. whenthe latch pin 76 engages ram 16 via its tongue 82 and a wall of groove81, all movable parts are mechanically interlocked and may be moved inuniosn by manipulation of lever 17. When the tongue 82 is in groove 72,manipulation of the lever 17 may occasion hydraulic operation byreciprocation of crosshead 46, piston rod 38, and piston 47, relative topump barrel 32, but it will not alford direct mechanical movement of ram16.

Assuming the parts to be in the position shown in the drawings and withno obstacle beneath the ram 16; downward movement of lever 17 will carryram 16, piston 23 and pump 31 together in the same direction. Duringsuch motion fluid will be drawn from the reservoir 89, through checkvalve 29 and into cylinder 22 above piston 23, this movement may becontinued for the full stroke of the thrustings section. If, however,the ram meets an obstacle offering suicient resistance, the bevel(angular) engagement of tongue 82 with the lower wall of groove 81 willforce latch pin 76 back against the bias of spring 79 and allow guidesleeve 68, inner crosshead 46 and piston rod 38 with piston 47 andbushing 51 to move downwardly1 of pump barrel 32. During this motion,tongue 82 will first ride on the ram wall above slot 72 and then dropinto the said slot to allow free operation of the parts involved.Continued downward movement of the actuating section will, becausebushing 51 has contacted O ring 49 and so closed passage 48, force fluidthrough ports 36 into annulus 42 and on into the working cylinder 22 toapply hydraulic pressure on to the piston 23 and ram 16; at the sametime more uid will be drawn past valve 57 into barrel 32. If the motionof lever 17 is new reversed, piston rod 38 will move bushing 51 upwardaway from O ring 49 allowing cruciform washer 52 to engage the loweredge of piston 47 and carry it upward, with passage 48 open, and iluidin the barrel 32 will pass beneath piston 47 and become available fordisplacement into cylinder 22. If lever 17 is further reciprocated, thepumping action will continue to move the thrusting section downward,tongue 82 being in slot 72 throughout the whole cycle. By virtue of thevalve action above described, the ram may be left locked under hydraulicload for as long as desired.

To release the ram and move it upward, lever 17 is moved upward to causetongue 82 to ride over the bevelled end of slot 72 and pass on intogroove 81 and partly across it, at which time the tip of piston rod 38will strike valve 57 and move it sideways from its seat, during thistrain of events passage 48 will be held open by piston 47 striking ring67 so that it cannot be carried, by the ow of liuid passing throughpassage 48, into contact with bushing 51. The movement of piston rod 38while unseating valve 57, is accompanied by the compression of spring 84which affords a distinct feel and obviates accidental release ofpressure. After pressure has been released, contact of crosshead boss 83with the lower face of plug 37 will cause the ram to rise without thevalve S7 being squeezed by the piston rod 38.

The parts should be so proportioned that upward travel of lever 17 islimited by contact between the upper surface of sleeve 68 and housing 18so as to avoid undue pressure on the bottom face of plug 37 or otherinternal parts.

The foregoing description concerns an embodiment o( the invention in asmall press that may be left locked, under load, and may also be pumpedthrough any portion of its stroke. A simplified version is alsopractical for many uses (rivet heading, staking and marking for eX-ample) wherein the whole valve unit, 55, may be omitted. Such a presswould then, as before, operate hydraulically at any point of its stroke,but only for the relatively short distance afforded by a single strokeof pump 31 nor could it be locked under load. For example, a presshaving a working cylinder of lll/s" bore and a pump cylinder of 52/16bore by 1% stroke would atiord a high pressure (hydraulic) stroke ofapproximately g", which is adequate for many purposes.

A noteworthy feature of the construction ldisclosed is the ease withwhich it may be serviced. After emptying out the working fluid the wholeinternal mechanism with its seals, valves, etc. (i.e. cylinder head 25,ram 1.6, piston 23, pump 31 and associated O ring seals) can bewithdrawn as a unit upon removing split ring 27 and wrist pin 70 andthen loosening screws 74 to allow latch pin 76 to clear the ram 16;thereafter the internal mechanism may be replaced and secured byreversing the disassembly process. This permits simple unit exchange andsubsequent part repair at convenience.

It will thus be seen that the objects set forth above and those madeapparent from the preceding description, are efficiently attained, andsince certain changes may be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. A hydraulic device comprising a movable ram for operating upon aworkpiece, a uid reservoir, pump means for feeding fluid under pressurefrom said reservoir to said ram, said pump means being carried by andmovable with said ram, and actuating means for moving said ram intoengagement with a workpiece and for thereafter actuating said pump meansto supply said fluid under pressure to said ram.

2. The apparatus according to claim 1 wherein said device comprises abody having the reservoir for said uid located therein and a workingcylinder with a head, the ram having one end located within said bodyand having attached thereto a piston cooperating with said cylinder.

3. A device according to claim 1 having a body section comprising saidreservoir and a pressurizable working cylinder having a cylinder head, apiston in said cylinder attached to said ram and movable therewith byfluid pressure, said actuating means being supported at least in part bysaid body section and having a connecting member movable relative tosaid ram for actuating said pump, said actuating means including meansengageable with said arm to move the same without relative movement ofsaid connecting member.

4. A device according to claim 3 wherein said body section is arelatively rigid structure comprising a guide for said ram and a housinghaving a chamber constituting the reservoir and the cylinder, thecylinder head being secured within the chamber and serving as apartition between the reservoir and the cylinder, the said pump having apump piston and extending axially of the ram adjacent the rst mentionedpiston and the connecting member being within a cavity in said ram, theram and ram guide having axially extending openings affording accessinto said cavity for connecting means to operably connect said actuatingmeans with said connecting member, means for engaging with said ram-comprising a coupling and decoupling member extending from theactuating means through the said openings to the ram whereby saidactuating means may be coupled with and decoupled from the ram, the ram,the pump, the pump piston and the actuating means being thereby movabletogether in unison and whereby said actuating means may affect themovement of said pump piston without directly affecting movement of saidram when said means for engaging with said rams decouples said ram andsaid actuating means.

5. A device according to claim 3 wherein said pump comprises a valve anda portion movable ybetween limits to cause said pump to supply uid underpressure to said cylinder and wherein said portion is movable beyond oneof said limits to open said valve and permit the ow of fluid from saidlcylinder and thereby release tluid pressure therefrom.

A6. A device according to claim 4 wherein the movement of the connectingmember is a reciprocating movement, and the pump comprises a barrellocated at least partly within the cylinder and having a part in fluidconducting communication with the reservoir, the barrel having a closureat one end, a rod assembly attached to said pump piston and ypassingwith sliding sealing engagement through said closure and extending therebeyond into the `cavity and being connected to said connecting member,said pump piston and said rod assembly consituting a delivery valve inthe pump adapted on reciprocation by movement of the connecting memberto draw fluid from the reservoir through said part in communicationtherewith and to deliver fluid inside said cylinder.

7. A device according to claim 4 wherein said cylinder head, saidpiston, said ram and said pump are secured as t0 be removable as asingle assembly from said body section after releasing said cylinderhead for Withdrawal from said chamber and disengaging said coupling anddecoupling means and said actuating means from said ram.

8. A hydraulic device of the class described, comprising a movable ramfor operating on a workpiece, a body having located therein a reservoirfor uid, and a working cylinder with a -cylinder head having an apertureformed therein, a piston located in said working cylinder and secured tosaid ram, a pump carried by and movable with said ram, for supplyingfluid from said reservoir under pressure to said cylinder to operatesaid piston, said pump comprising a cylinder barrel coaxial with saidram located -partly within said working `cylinder and passing via saidaperture in said cylinder head partly into said reservoir, sealing meansfor sealing the wall of said aperture and said barrel, said ram having acentral cavity extending axially thereof away from said pump, means foractuating said pump located outside of said body and pivotably connectedthereto, said actuating means including a guide slidable upon a portionof said body and having connecting means extending into said ram cavityfor actuating said pump and including coupling means for selectivelyengaging said ra-m for movement prior to actuation of said pump.

9. A device according to claim 8 wherein the means for operating saidpump comprises a crosshead, said connecting means from said actuatingmeans being connected to said crosshead, a piston rod exten-ding fromsaid crosshead and having a piston at the end thereof operativelylocated within the pump, said rod having an extension and said pumpcomprising an intake valve openable against uid pressure by said pistonrod extension, sealing mean surrounding said rod for sealing said rodwithin the pump barrel and compression spring means between said sealingmeans and said crosshead for biasing said rod away from said intakevalve `whereby said actuating means is required to overcome the bias ofsaid spring in order to move said rod beyond its normal operative strokeand open said intake valve.

References Cited UNITED STATES PATENTS 2,490,284 12/1949 Simart 60-522,563,912 8/1951 Belinkin 60--52 XR EDGAR W. GEOGHEGAN, PrimalyExaminer.

1. A HYDRAULIC DEVICE COMPRISING A MOVABLE RAM FOR OPERATING UPON AWORKPIECE, A FLUID RESERVOIR, PUMP MEANS FOR FEEDING FLUID UNDERPRESSURE FROM SAID RESERVOIR TO SAID RAM, SAID PUMP MEANS BEING CARRIEDBY AND MOVABLE WITH SAID RAM, ACTUATING MEANS FOR MOVING SAID RAM INTOENGAGEMENT WITH A WORKPIECE AND FOR THEREAFTER ACTUATING SAID PUMP MEANSTO SUPPLY SAID FLUID UNDER PRESSURE TO SAID RAM.